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  <title>Get the read preference for this database</title>

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</div><hr /><div id="mongodb.getreadpreference" class="refentry">
 <div class="refnamediv">
  <h1 class="refname">MongoDB::getReadPreference</h1>
  <p class="verinfo">(PECL mongo &gt;=1.3.0)</p><p class="refpurpose"><span class="refname">MongoDB::getReadPreference</span> &mdash; <span class="dc-title">Get the read preference for this database</span></p>

 </div>

 <div class="refsect1 description" id="refsect1-mongodb.getreadpreference-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="modifier">public</span> <span class="type">array</span> <span class="methodname"><strong>MongoDB::getReadPreference</strong></span>
    ( <span class="methodparam">void</span>
   )</div>

 </div>


 <div class="refsect1 parameters" id="refsect1-mongodb.getreadpreference-parameters">
  <h3 class="title">参数</h3>
  <p class="para">此函数没有参数。</p>
 </div>


 <div class="refsect1 returnvalues" id="refsect1-mongodb.getreadpreference-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">This function returns an array describing the read preference. The array contains the values <em>type</em> for the string read preference mode (corresponding to the <a href="class.mongoclient.html" class="classname">MongoClient</a> constants), and <em>tagsets</em> containing a list of all tag set criteria. If no tag sets were specified, <em>tagsets</em> will not be present in the array.</p>
 </div>


 <div class="refsect1 changelog" id="refsect1-mongodb.getreadpreference-changelog">
  <h3 class="title">更新日志</h3>
  <p class="para">
   <table class="doctable informaltable">
    
     <thead>
      <tr>
       <th>版本</th>
       <th>说明</th>
      </tr>

     </thead>

     <tbody class="tbody">
      <tr>
       <td>1.3.3</td>
       <td>
        The return value has changed to be consistent with
        <span class="methodname"><a href="mongodb.setreadpreference.html" class="methodname">MongoDB::setReadPreference()</a></span>. The
        <em>type</em> value was changed from a number to a string,
        <em>type_string</em> was removed, and
        <em>tagsets</em> now expresses tags as key/value pairs instead
        of colon-delimited strings.
       </td>
      </tr>

     </tbody>
    
   </table>

  </p>
 </div>


 <div class="refsect1 examples" id="refsect1-mongodb.getreadpreference-examples">
  <h3 class="title">范例</h3>
  <div class="example" id="example-1395">
   <p><strong>Example #1 <span class="methodname"><strong>MongoDB::getReadPreference()</strong></span> return value example</strong></p>
   <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /><br />$m&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">MongoClient</span><span style="color: #007700">();<br /></span><span style="color: #0000BB">$db&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$m</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">test</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$db</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">setReadPreference</span><span style="color: #007700">(</span><span style="color: #0000BB">MongoClient</span><span style="color: #007700">::</span><span style="color: #0000BB">RP_SECONDARY</span><span style="color: #007700">,&nbsp;array(<br />&nbsp;&nbsp;&nbsp;&nbsp;array(</span><span style="color: #DD0000">'dc'&nbsp;</span><span style="color: #007700">=&gt;&nbsp;</span><span style="color: #DD0000">'east'</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'use'&nbsp;</span><span style="color: #007700">=&gt;&nbsp;</span><span style="color: #DD0000">'reporting'</span><span style="color: #007700">),<br />&nbsp;&nbsp;&nbsp;&nbsp;array(</span><span style="color: #DD0000">'dc'&nbsp;</span><span style="color: #007700">=&gt;&nbsp;</span><span style="color: #DD0000">'west'</span><span style="color: #007700">),<br />&nbsp;&nbsp;&nbsp;&nbsp;array(),<br />));<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$db</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">getReadPreference</span><span style="color: #007700">());<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
   </div>

   <div class="example-contents"><p>以上例程会输出：</p></div>
   <div class="example-contents screen">
<div class="cdata"><pre>
array(2) {
  [&quot;type&quot;]=&gt;
  string(9) &quot;secondary&quot;
  [&quot;tagsets&quot;]=&gt;
  array(3) {
    [0]=&gt;
    array(2) {
      [&quot;dc&quot;]=&gt;
      string(4) &quot;east&quot;
      [&quot;use&quot;]=&gt;
      string(9) &quot;reporting&quot;
    }
    [1]=&gt;
    array(1) {
      [&quot;dc&quot;]=&gt;
      string(7) &quot;west&quot;
    }
    [2]=&gt;
    array(0) {
    }
  }
}
</pre></div>
   </div>
  </div>
 </div>


 <div class="refsect1 seealso" id="refsect1-mongodb.getreadpreference-seealso">
  <h3 class="title">参见</h3>
  <ul class="simplelist">
   <li class="member">The <a href="mongo.readpreferences.html" class="link">read preferences</a> documentation.</li>
  </ul>
 </div>


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